1. Field of the Invention
The present invention relates locking fasteners and shackle assemblies. More particularly, the present invention relates to a fastener with a locking ring and use of the fastener in a shackle assembly.
2. Description of the Prior Art
Traditionally, a shackle has a U-shaped metal bracket (also known as a clevis) with two arms. The ends of the two arms span an opening between them, which is closed with a bolt or clevis pin inserted through openings in the ends of the arms. Shackles are commonly used to connect multiple items together or secure items to a chain or rope. In some cases, the user loops one end of a strap around the clevis or clevis pin with the other end of the strap being secured to a fixed object. Similar to a bolt, one end of the clevis pin often has an enlarged head or cap that prevents the pin from passing completely through openings in the clevis arms. The opposite end of the clevis pin has a hole passing transversely through the pin's end. A clevis pin may be held in place by inserting a cotter pin or other retaining device through the hole in the end of the clevis pin, thereby preventing the clevis pin from passing through the holes in the clevis. In other shackles, the clevis pin is secured by nuts screwed onto one or both ends of a threaded clevis pin. In yet other designs, the clevis pin is retained by a retaining ring (e.g., an E-ring) placed around a recess or groove in the end of the clevis pin.
A related device, known as a hammerlock link, is useful to connect two closed loops, such as chain links. A hammerlock link has two U-shaped metal pieces connected together at the ends of each arm of the U-shaped pieces. Each U-shaped piece has an open end defined by a pair of arms forming the U shape. Each arm of the U-shaped piece has an opening passing transversely through the end of the arm, much like a clevis. The openings in the ends of the arms of both U-shaped pieces are aligned and connected together with a pin that inserts through the openings. The pin in some hammerlock links is held in place by placing a split sleeve over a middle portion of the pin positioned between the U arms of each U-shaped piece. The outer diameter of the split sleeve is larger than the openings in the arms and therefore prevents the pin from sliding out through these openings.
With both a hammerlock link and with a clevis, the user assembles a pin through a U-shaped piece to form a closed loop and retains the pin in place with fasteners or additional parts as described above.